More than 40 million masks are on the way to help protect frontline health workers after weeks of confusion and fear about the supply of Covid-19 equipment.

Up to 11 privately chartered planes full of personal protective equipment (PPE) - masks, gloves, gowns and visors - are also due to begin landing soon.

The government had recently ordered the release over coming weeks of at least 11 million masks from pandemic reserves, prompting questions by Wellington thinktank the McGuinness Institute on how much PPE was left.

Director-General of Health Ashley Bloomfield told RNZ on Wednesday more supplies were due to arrive over the next few weeks.

"Last night, we confirmed an order for 41 million additional face masks that will start to arrive on Monday and continue to be delivered over the next six weeks.

"We have also placed an order for an additional 500,000 isolation gowns, 30,000 face shields and 50,000 goggles, which are scheduled to arrive over the coming weeks.

"There is plenty of PPE available in New Zealand."

District Health Boards were leading the distribution of the masks, with the ministry meeting for each of the past three days with health sector unions to reassure them about PPE stocks, and advise them on when workers should use it, Ashley says.

Other PPE for health workers outside of DHBs, such as in medical centres and community health agencies, are also on their way, with the first of three Dreamliners chartered by Whanganui importer Amtech due to land in Auckland from China on Saturday.

A second is due on Sunday, a third next Wednesday.

The triple payload included almost two million masks,150,000 face shields, 100,000 goggles and an unspecified number of gowns - all pre-ordered and paid for, Amtech director Jeremy Anderson says.

Another three flights are being teed up.

The profit margin was low as charters cost a lot and his motivation was to help, Jeremy says.

At least two other companies are also bringing in planes with PPE. In one of those cases, The Warehouse founder Sir Stephen Tindall is using his China sourcing office and personally underwriting the cost of the PPE, being imported with help from toy company Zuru.

Jeremy says the PPE raw material was very difficult to get now.

The whole world is now wanting PPE gear. If it spreads around the third world countries, the demand for PPE is just going to explode.

"And there will come a point where China cannot keep up, and we're waiting a long time [for orders], and that would be a a scary situation."

The market was being hammered by the US, he says.

"I've been even getting calls from contacts in New York for volumes of 10 million masks and 20 million masks ... we could never possibly do those sort of numbers."

Prices are rising. A full-filter N95 mask bulk-bought for 32 cents in China pre-Covid, now costs $2.80.

But the thornier issue for Jeremy is time - logjammed factories pushing back orders ever further.

He was worried in case the Chinese government were to clamp down on PPE exports - "not that it's been mooted".

Ashley says they were looking ahead.

"We are ... following up further channels for additional PPE, for example we are in negotiations to secure an additional 20 million masks per month from another supplier."

New Zealand businesses are exploring ways to produce masks and gowns locally.

However, the raw material - a non-splash, semi-absorbent fabric called 30-50 GSM coated, spun bond polypropylene non-woven - is not made here.

At least one factory, which did not want to be identified, has gone looking but been unable to import any.

The new supplies of PPE will replenish depleted public stocks, with 1.8 million masks having been sent out by DHBs in the last week and about another 9 million poised for distribution.

The McGuinness Institute expressed concern about reserves after pursuing numbers from the ministry and DHBs for weeks.

Just how large the reserves were for each item of PPE remained unclear, institute chief executive Wendy McGuinness says.

"My recommendation is the Office of Auditor-General actually audits the Ministry of Health stock that relates to Covid-19 and makes that audit public, so that all the press, decision-makers, businesses doing purchases, everyone has enormous clarity," says Wendy.

"It has enormous priority because if we don't know what we've got, we won't know what to buy, and we won't know what to ration, and we won't know what to manufacture."

The Ministry of Health says from now, non-health essential services will receive PPE via office supplies company and distributor National Express Products operating under the Ministry of Business Innovation and Employment.

Phil Pennington/RNZ